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1、Int. Journal of Refractory Metals and Hard Materials 41 (2013) 8589Contents lists available at ScienceDirectInt. Journal of Refractory Metals and Hard Materialsj o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / I J R M H MFabrication of diamond particles reinforced Al-ma
2、trix composites by hot-press sinteringJianping Long, Xin Li , Dedi Fang, Peng Peng, Qiang HeCollege of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu 610059, Peoples Republic of Chinaa r t i c l e i n f oArticle history:Received 22 October 2012 Accepted 8 F
3、ebruary 2013Keywords:Vacuum hot-pressing sintering Diamond/AlElectronic packaging Thermal conductivityCoefficient of thermal expansiona b s t r a c tAl-matrix composites reinforced by 50 vol.% diamond particles under a 60 MPa sintering pressure were fab-ricated by a vacuum hot-pressing method. The c
4、omposite obtained a relative density of 96.5%. The coefficient of thermal expansion (CTE) and the thermal conductivity (TC) of the diamond/Al composites were measured by the laser flash method and differential dilatometry, respectively. Results showed that diamond/Al composites have high TC and low
5、CTE with high sintering pressure (60 MPa) and high volume fractions of diamond particles (50 vol.%). The TC of the 50 vol.% diamond/Al composite was 321 W/mK, which is 112 W/mK higher than that of pure Al (209 W/mK). At temperatures ranging from 298 K to 573 K, the com-posite obtained low CTEs in th
6、e range of 13.2 106/K to 8.3 106/K, which satisfied the CTE of electronic packaging materials. The CTE values obtained in the experiment were approximately equal to the CTE calcu-lated by the Kerner model 17. The effects of volume fractions of diamond particles and sintering pressure on the density,
7、 TC, and CTE of diamond/Al composites were investigated. 2013 Elsevier Ltd. All rights reserved.1. IntroductionBoth miniaturization of electronic components and increase in packaging density in microelectronic and semiconductor devices lead to problems that prevent currently used electronic packagin
8、g materials from meeting the requirements of a heat sink and a heat spreader 1,2. A new electronic packaging material with high thermal conductivity (TC) and low coefficient of thermal expansion (CTE) must be developed to increase the reliability of electronic packaging materials. The CTE of these m
9、aterials must match that of semiconduc-tor materials, including GaAs and Si 3. Low CTE combined with slightly high TC (less than 200 W/mK) of metal matrix composites (MMCs), such as aluminum (Al) reinforced with SiC particle or carbon fiber composites 47, are used in electronic packaging. Despite th
10、e above, the TC of the MMCs used in electronic packaging cannot meet the future requirement because the highest power density of high-power integrated circuit will reach to 100 Wcm2.Considering the continuing decrease in the cost of diamond in re-cent years and the superior properties of high TC (ma
11、ximum ranging from 1800 W/mK to 2000 W/mK at 298 K) combined with low CTE 8,9, diamond should be an ideal reinforcement for MMCs used in electronic packaging. In a previous study, diamond/Al composites were produced by spark plasma sintering 19, gas pressure infiltration, and squeeze casting infiltr
12、ation 10. Squeeze casting infiltration and gas pressure infiltration are regarded as the most promising amongCorresponding author. Tel.: +86 28 84079027. E-mail address: (X. Li).these methods. However, these techniques require high energy and cause the formation of Al2OC in the interface layer of d
13、iamond and Al during fabrication. These carbides may lead to adverse effects on the interface bonding 10.The present study examined the fabrication of diamond/Al com-posites by a simple hot press (HP) method. The HP method can pro-duce diamond/Al composites below the melting point of Al. Therefore,
14、harmful interface reactions between diamond and Al can be prevented. However, inappropriate amounts of HP sintering pressure can easily lead to a low relative density of composites prepared by the HP method. Consequently, varying levels of sintering pressure were applied to in-vestigate the influenc
15、e on RD, TC, and CTE.2. Experimental2.1. Materials and methodsAl powders (purity 99.5%, Kelong, China) were used as matrix materials. Single-crystal diamond particles (Yangzhou Grinding Tools Co. Ltd., China) with sizes ranging from 55 m to 70 m were used as reinforcement for composites.The diamond/
16、Al mixture powders were prepared by planetary ball mill mixing (Experiment Instrument Research Institute, China) at 300 rpm for 4 h with a ball-to-powder ratio of 2:1. The obtained powders were cold pressed in a 50 mm diameter steel mold.The acquired cold-pressed compacts were sintered in a 50 mm diameter graphite mold by using an HP device with induction heating (Huachen Electric Furnace Co., Ltd., China). As illustrated in Fig. 1,0263-4368/$
